naming weeds: hello, galinsoga and commelina

I HAD TO LAUGH when I read that Galinsoga, a vegetable-garden weed I’m all too familiar with (photo above), is also known as “gallant soldier” for marching forward energetically. A trooper, indeed. And finally—finally!—I know the name of the blue-flowered thing that looks like someone dropped some pieces of their spiderwort houseplant in my garden. Hello, Commelina. As always, I’m encouraging myself (and you) to put names to our weeds, because knowledge is power when it comes to beating them. This week, two more names to perhaps add to your list. Anybody look familiar?

galinsoga wastes no time

GALINSOGA is also called quickweed; the Rutgers weed database says that’s because the seeds that follow its tiny, daisy-like yellow and white flowers start to germinate on their way to the ground—no waiting, and quick enough to produce multiple generations each growing season.

More than one species are listed in weed books; I have G. quadriradiata, which I actually know as its synonymous name G. ciliata, and I know just where it came from. A friend in New York City shared a desired plant a decade ago, and a gallant soldier was lurking in the pot, a hijacker. (Originally, it’s from South America, but is now widespread in the U.S.)

I recommend pulling this one as soon as it emerges–it thankfully comes out easily when young–or using a hoe to dislodge seedlings, being sure never to let it establish and flower. With repeat weeding or cultivating, I have kept it from becoming a wider issue.

Remember that a shovel with clods of dirt remaining on it, used in an infested bed then used in an infested one, can spread seeds of things like Galinsoga. Clean tools between uses if you’re working around seedy weeds.

a weedy spiderwort: commelina communis

FOR YEARS, as mentioned, I’ve half-imagined that bits of a former resident’s spiderwort houseplant had jumped out the window and planted themselves in the garden, but of course that’s not the story. (If I lived in Florida or another warm zone, a “houseplant” a subtropical Tradescantia might in fact be one of my toughest weeds.) But for me the story is the Asiatic dayflower, Commelina communis, another widespread invader from (you guessed it) Asia. It’s in the same family as Tradescantia, so you, too, may notice a resemblance. This one has small blue flowers.

There’s a native American Commelina species called C. erecta, but we don’t seem to have it hereabouts, according to reference sources on local flora. And besides, this particular pest I’m always pulling around now only appears in semi-shady to shady, cultivated spots in my garden where the soil’s been disturbed and I’ve brought in things from the nursery: classic weed modus operandi. Commelina communis is another common hitchhiker, especially pesky for garden centers. This IowaPlants.com page has a very detailed set of photos of all its parts, if you want to do a closer ID.

Asian dayflower is an introduced annual that reproduces by seed, says the UMass-Amherst Extension, which has good photos of a thick stand of it in flower. I’m happy to have no such photo of my own; that’s a situation I work my best to prevent happening here by pulling or hoeing the emerging seedlings, as with the Galinsoga.

ah, the order of things

I KNOW, you’re probably thinking: Doesn’t she have anything to do with herself but figure out the names of her weeds, poor lonely woman? (That’s clearweed, or Pilea pumila, above.)

No worry; I haven’t completely lost it, or drifted away from civilization. This feels good.

There’s an expression, “A place for everything, and everything in its place.” Well, there is something about naming my weeds, putting one or two more a week into its place in the (dis)order of things, that I’m finding to be a lot like that. Even in the early summer jungle—which is what a garden after so much rain wants to be right now, flexing its unruly muscle at me—it feels comforting, and empowering.

Oh, and I love any excuse to stop all this incessant weeding and go inside, make a cup of tea, and look things up.

comments

Unfortunately I have planted a variety of horsetail weed.
It looks beautiful in flower arrangements, however i can’t get rid of it from the bed it was in and has now spread into the lawn and other beds.
If you have knowledge of how to get rid of this pest, please let me know.

The only thing I hate about gardening….weeding. Hate it, hate it, hate it. I have a large section of my herbaceous perennial beds (about 1,000 sq ft) that can become –and stay– very moist after heavy rains. I’ve taken care with the plants selected to ensure that they thrive in this nutrient-dense, moist environment, but oh, the weeds here! Clearweed is a daily irritant; it’s only redeeming feature is that it is so easy to pull. My new nemesis is a matting moss-like, spreading weed that forms a dense, shallow root mass and spreads like crazy. I wish I knew its name so I could curse at it with more familiarity. Any ideas?

I do want to alert folks who may not know about it, to a fantastic weeding tool: a small, lightweight garden blow torch. (Here’s one just for illustrative purposes, but there are many out there on Amazon: https://www.amazon.com/dp/B00DJ62JO2/ref=sr_1_9?ie=UTF8&qid=1500297841&sr=8-9&keywords=garden+blow+torch This one is only $27.) I use this darn thing everywhere. Between pavers, along the edge of curbs, between rocks in my hardscaped stone steps, and all over my raised bed veg garden’s pathways. The heat is very intense, but very targeted, and I use it sweeping alongside the wooden raised bed timbers with no harm to the wood. I can completely weed all my chipped pathways in as much time as it takes to walk all the pathways slowly, sweeping the torch 3″-4″ above the soil level, slowly from side to side. Picture someone using a metal detector on the beach.) The flame is so hot that it is invisible, and the weed plant barely looks affected until about 15 minutes later when it has completely collapsed and died. I attach mine to a small propane cylinder which I carry on a cross body shoulder strap. It’s a godsend. But I dare not use it inside the beds near plant stems, so my cursing the creeping green moss-like weed continues! Any suggestions other than keeping on top of it?

I learned about Galinsoga after a trip to Colombia, looking for more information on a culinary herb in local dishes–Guascas. I bought dried while there; for a long time a friend from Canada was more than happy to bring me her “weeding” when we met at a conference once a year. Same moral here: eat your weeds!

Sometimes I wonder if all the stress over weeds etc is worth it. I live in upstate NY, inside the Adirondack State Park. We do have lawns but little in the way of gardens. The “green” surrounding us is so lush – weeds , native plants and all. We’ve yet to really do much gardening and I am loathe to make this beautiful place into just another job to do. I do admit that the wild comfrey is a real pain, but the insects love its flowers. Pots and baskets here and there more than suffice. Have seen many of the weeds you named, but haven’t had the urge to eradicate them. Living on the wild side and enjoying it so much more !

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Quotes

All that live must die, passing through nature to eternity.

—Shakespeare, from 'Hamlet'

Welcome! I’m Margaret Roach, a leading garden writer for 25 years—at ‘Martha Stewart Living,’ ‘Newsday,’ and in three books. I host a public-radio podcast; I also lecture, plus hold tours at my 2.3-acre Hudson Valley (NY) Zone 5B garden, and always say no to chemicals and yes to great plants.